In the world of governance, unwritten principles of statecraft require that all organs of state work in harmony with each other, even when each maintains its separateness and independence. This is particularly the case in states that have “republican” forms of governance and in some monarchies, termed constitutional monarchies.
In those monarchies, governance is a mixture of traditions, paying homage to individuals called king/queen as symbols of state and the actual governors of that state. Irrespective of the form, governance is a blend of chosen institutions, working together in the interest of the state. Each is, or should be, manned by individuals with clear understanding of what the national interests of the particular state are.